1. Field
The disclosure relates to mesh networks. More particularly, the disclosure relates to a method and apparatus for managing data flow through a mesh network.
2. Background
In recent years there has been an increase in demand for ubiquitous access to high speed data services. The telecommunication industry has responded to the increase in demand by offering a variety of wireless products and services. In an effort to make these products and services interoperable, the Institute for Electrical and Electronics Engineers (IEEE) has promulgated a set of wireless local area network (WLAN) standards, e.g., IEEE 802.11. The products and services that conform to these standards are frequently networked in a wireless point to multipoint configuration. In this configuration, individual wireless devices (e.g., stations) communicate directly with an internet access point. Each of the wireless devices shares the available bandwidth.
A more efficient and resilient network can be realized through the use of a mesh network. A mesh network is a distributed network having multiple wireless mesh points. Each mesh point in the mesh network may act as a repeater receiving traffic, transmit or transport streams (TSs) and relaying the TSs to the next mesh point. A TS proceeds from an originating mesh point to a destination mesh point by “hopping” from mesh point to mesh point. TS routing algorithms ensure that TSs are routed efficiently from the origination mesh point to the destination mesh point. TS routing algorithms may dynamically adapt to changes in the mesh network and make the mesh network more efficient and resilient. For example, in the event a mesh point is too busy to handle the TS or a mesh point has dropped out of the mesh network, the TS routing algorithm may route the TS to the destination mesh point through other mesh points.
The destination mesh point is frequently a mesh portal. TSs arriving at the portal may be decoded and reformatted for retransmission over other networks, for example, the Internet. A TS originating at a mesh point and traveling toward the mesh portal is referred to as an upstream TS. A TS coming from a mesh portal and traveling toward a destination mesh point is referred to as a downstream TS. A mesh point that is a single hop away from a mesh portal is said to be a mesh point of rank 1. A mesh point that requires at least two hops to reach a mesh portal is said to be a mesh point of rank 2. In general, a mesh point that requires n hops to reach a mesh portal is said to be a mesh point of rank n.
Large percentages of a mesh network's traffic flows are upstream and downstream TSs. Upstream TSs generally hop from higher ranked mesh points to lower ranked mesh points before departing through a web portal. Downstream TSs generally hop from lower ranked mesh points to higher ranked mesh points. Thus, lower rank mesh points support the traffic flows of higher rank mesh points resulting in more TS congestion around the lower rank mesh points. In general, mesh points of rank 1 are likely to support more upstream and downstream TS than mesh points of rank 2. Similarly, mesh points of rank 2 are likely to support more TS than mesh points of higher ranks (e.g., 3, 4, etc.).
The mesh network topography, in which lower rank mesh points support upstream and downstream traffic flows from higher rank mesh points, often results in TS flow congestion at mesh points near the web portals. Many factors contribute to flow congestion including: neighboring mesh points attempting to access the communication channel medium too frequently; neighboring mesh points transmitting at lower data rates than optimum at the physical access layer; neighboring mesh points transmitting bursts that occasionally exceed the negotiated access throughput; poor radio conditions between the downstream mesh point and the upstream mesh point resulting in a lower than expected throughput.
It has been recognized by those skilled in the art that apparatuses and methods for reducing mesh congestion and improving data handling at individual mesh points can improve the efficiency and reliability of a mesh network.